Fire alarm



July 20 1926. 1,593,002

0. A. ZAHNER FIRE ALARM Fild August 29, 1925 oscma A. ZAHNER.

INVENTOR f1 TTORNE Y Patented July 20, 1926.

UNITED STATES osoAn, A. 2411mm, or sr. LOUIS, MISSOURI.

FIRE ALARM.

Application filed August 29, 1925. Serial 1%. 53,267.

My invention relates to improvements in fire alarms and more particularly to those fire alarms that areautomatic in their action, the same being set to go off at a tem- 6 perature that is dangerously above thatnormally existent in the particular location in which the alarm is placed.

Such alarms are not broadly new, but they are quite apt to become inoperative 10 through their becoming clogged with dirt, dust and the like, and in those alarms using fusible wax plugs or inserts, the alarm is apt to become inefficient through the hardening of the wax through age, thus causing the wax to melt at a higher temperature than intended, and in turn causing the alarm to go off at a temperature much higher than the desired critical temperature.

One of the objects of my invention is to provide an automatic fire alarm that will reset itself automatically after giving an alarm, and that will not require the replacement of fresh wax inserts or links after each alarm.

Another of the objects of my invention is to provide a fire alarm of the kind described, -wherein the controlling element will be in the form of a coiled thermostatic metal, a suitable link-work being interposed between said thermostaticmetal and the escapement of a clock-work mechanism to normally hold the escapement against movement, but permit movement of the latter as,

soon as the desired temperature is reached.

Another of the objects of my invention is to provide means for adjusting the control means for said escapement so that the escapement will be released at selectively adjustable temperatures.

The invention has among its other objects the provision of an alarm of the kind described, which shall be simple, convenient, economical, reliable, and efficient and satisfactory for use wherever found applicable.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art to which this invention appertains from the disclosures herein given.

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts Figure I is a top plan view of the device, a part of the gong being broken away in order to show the construction more clearly;

Figure 11' is a view in elevation of the same, showing the gong in section; and

Figure III is a detail showing a thermostatically-controlled movably adjustable electrical terminal.

In the drawings, wherein I have illus trated the preferred embodiment of my invention, there is shown a fire alarm having an operating mechanism consisting of a spring-wind clock-work mechanism indicated generally by the reference character A, the frame-work of the same comprising the parallel plates 1 and 2, of any suitable shape and material. Posts 3 connect these plates, and if desired, one end of the winding spring 4 ma be fixed to one of the posts as shown. or the purpose of winding the spring, a key 5 is provided beneath the gong 11. e

A train of gearing 6 is operatively connected to the winding spring, the last gear of the train engaging with an escapement 7 pivotally mounted between the plates of the frame-work by means of the arbor 8. A pin 9 is fixed to and carried by the escapement arbor 8 so as to be oscillated thereby when the escapement oscillates. Loosely connected to the end of the escape ment 1s a clapper 10, of any desired construction, the same being adapted to strike or ring the gong 11, the latter covering the moving parts of the entire mechanism so as to substantially exclude dirt therefrom, said gong being removably mounted upon the frame-work of the clock-work mechanism by means of any suitable, fastening means, as for instance by the knurled nut 12. The clapper will strike the gong intermittently, in the usual manner, whenthe esca ement oscillates.

11 order to normally hold the clapper from strikin the gong, I have provided thermostatically-controlled means, said means normally holding the escapement in its locked position, but releasing the same to permit the clapper to strike the gong when the temperature 1n the place in which the alarm located reaches a predetermined point, and automatically returning to normal position to reset the escapement, after the critical tem erature drops.

This last-mention c means comprises an element of thermostatic metal suitable for the purpose, made in the form of a coil 13, the outer end of which is fixed to an ear 1 F struck up from one of the plates of the frame-work, as at 14, and the inner end of said coil having affixed thereto a rod 15, said rod being preferably arranged substantialiy perpendicularly to the plates. A pin 16 is fixedly attached to the rod 15 and extends angularly thereto for a purpose to be more clearly hereinafter described. It will be obvious that as the temperature rises, the coil 13 will tend to unwind or straighten out, thus partially rotating the rod 15 and the pin 16 carried thereby.

A double link 17-48 is interposed between the pins '9 and 16, one of the ends of each link bein slotted as shown, the slots being preferably closed. A second link 19 is pivoted at one of its ends to the adjacent ends of the link 1718, the other end of the link 19 being pivotally mounted between cars '20 preferabl struck up from one of the plates of the frame-work. A leaf sifting 2-1 is fixed at one end to one of the p ates, the other end of the spring pressing against the link 19 in the manner shown.

From the foregoing it is obvious that, whenever the thermostatic element 13 is actuated under the influence of heat, the pin is will swing in a clockwise direction (in the embodiment shown), thus forcing the lin 1'7'18 toward the right, and releasing the pin 9 from its locking engagement with the escapemcnt. In this position the escapement may freely oscillate, causing the alarm to be given by the clapper striking the gong. As soon as the temperature drops, the thermostatic element will automatically contract to normal os tion, and the other parts, including the link-work and escapement will again be intheir normal locked position, the "spring 21 assisting in brin n the parts to t eir normal positions, in w ic h position the gin 9 will be held in locked position against e inner end of the closed slot of the right hand member of the link 17-18.

it is quite desirable that some manner of adjustment be provided whereby the alarm maybe set to go oil at selectively adjustable temperatures, for it is obvious that if the alarm were originally intended to go off at a temperature of say 110 degrees it would be acceptable for use in the living rooms of a house, but would cause false alarms if it were placed in another Hart of the house, as for example in the urnace room. In

order to provide this adjustment, the link Eli--18 is preferably made so that one of the {two members, as for instance the member 18, 18 made of two parts, one slidablc longitudinally relatively to the other and held in adji ted relation by means of some suitable means such screws or the like. In this manner, the cilective length of the double link is varied, so that it the alarm is set for one of the higher temperatures of the range oi adjustment, the pin 16 must travel a greater distance, or with some play, before it strikes the end wall oi the slot of the link men'iber 16, thus moving the double link to the left to release the escapement. Any desired markings indicating the various tem perature adjustments may be provided upon the link li -1S, as shown.

Thus it will be seen that I have provided an automatic fire alarm that will be positive in its action, will have no parts tending to deteriorate through inaction, does not require the replacement of inserts, fuses or the like, and will "function elliciently at all times and through a range of adjustments.

here the alari is installed in a place in which the gong might not be heard, as for instance in a warehouse or factory, it is desirable to also inform a central oiiice or watchman oi the fact of the fire, and for this purpose an electric signal may be constructed as part oi the alarm, the signal, wir'ng and source of electrical energy being shown diagrammatically in the drawing.

The framework of the clock-work mechanism may constitute one of the electric tern'iinals oi the circuit, and the other terminal may be mounted so as to be movably adjustable relative to the pin 16, as shown. The latter terminal is suitably insulated from the framework as by the fibre pin 25, and is held in adjusted position by any desired means, as by the screws Markings similar to those upon the link 1718 may be provided for properly positioning the ad justable terminal 23.

The signal S will be actuated when the terminal 23 engaged by the pin 16 to close the circuit, thus indicating that the predetermined degree of heat in the vicinity of the coiled thermostatic metal element- 13 has been reached.

Itis obvious that the electrical signal S may be used either in conjunction with the mechanism operating the escapement, or operated in combination with a thermostatic coil alone.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination oi parts herein shown and described, or uses mentioned.

What I claim as new and desire to protect by Letters Patent is 1. In an automatic fire alarm, the combination with a clockwork mechanism, of an escapement for operating a gong, and means for normally holding said escapement in locked position and for releasing the same at a predetermined temperature, said means comprising a coil of thermostatically controlled material, a rod fixed to and carried by said coil, a plurality of slidably interconnected links operatively engageable directly between said rod and escapement, and means for varying the efiective length of said links so that the latter may be operatively engaged by said rod at selectively adjustable temperatures, whereby said escapement will be released by said links at selectively adjustable temperatures.

2. In an automatic fire alarm, the combi nation with a clock-work mechanism, of an escapement, a coil fixed at its outer end to the frame-work of said mechanism and carrying a rod at its inner end, a pin on said rod, a pin fixed to said escapement, an adjustable link engaging between said pins whereby the effective length of said link may be varied, and means for yieldably pressing said link toward said first-mentioned pin.

3. In an automatic fire alarm, the combination with a clock-work mechanism, of a clapper-operating escapement, a pin carried by said escapement, a coiled thermostaticmetal element fixed to the frame-work of said clock-work mechanism, a rod carried by said element so as to partially rotate when the element is actuated under the influence of temperature changes, a pin carried by said rod, a link engaging said pins at opposite ends, means for adjusting the effective length of said link, a second link pivoted intermediate the ends of said first named link and pivotally connected to the frame-work of the clock-work mechanism, and means for yieldably maintaining the end of said first-mentioned link in engagement with its adjacent pin.

OSCAR A. ZAHNER. 

